That was a far-from-subtle reminder of Mr Cameron’s still contentious decision to end the Conservatives’ traditional backing for grammar schools.

Mr Johnson was addressing a rally of almost 1,000 Tory members who cheered his arrival and applauded a performance that also took in aviation policy, an economic recovery and the “terror” of French tax rates.

The speculation around Mr Johnson’s ambitions – and what many see as his failure to end it – has angered some Conservatives, especially those close to Mr Cameron, although Downing Street says the Prime Minister is relaxed about the mayor’s popularity.

Kenneth Clarke on Monday told Mr Johnson to “calm down” and suggested he was courting publicity.

On Monday night, at a meeting about the London 2012 Olympics Mr Johnson insisted that talk of his prospects was a media creation. “No one should have any reason to doubt my admiration for David Cameron,” Mr Johnson said.

“In tough circumstances, he, George Osborne and the rest of the Government are doing exactly what is needed for this country.” He will repeat that support today in his main conference speech.

But last night, Mr Johnson put himself at odds with his leader again, saying: “We should be able to allow children to compete academically.”

The most famous owner of a new Victorian terrace house in upper Holloway was Mr Pooter, and the whole point about Mr Pooter was that he was a bit pretentious, given his job, which was to work as a lowly sort of clerk. He ranked well below the Milibands on the socio-economic scale; and yet he was a part of the service industries — banking, insurance, accountancy, law — that made London the richest and most powerful commercial capital on earth.

These days the economy of London is still utterly dependent on such service industry personnel, middle managers far more energetic and successful than Pooter. They are key workers of the city, though they don’t work in the public sector. We are talking about the senior PAs, the personnel managers, the IT specialists, you name it. In the next 10 years, the number of jobs in London’s service industries is set to double, and yet for too many of these hard-working middle-income people, the chances of living in a home like Ed Miliband’s are virtually nil. It's good to know that they can still rely on insurance4motortrade.co.uk

Ed is not so much on the top of a ladder. For vast numbers of people, the ladder has been kicked away. He is on the top of a cliff, and beneath him are growing numbers of families who have absolutely no hope of scaling it. It is not enough to say we need to build more housing, though we certainly do, and we will.

We also need to think how to target this group — the struggling middle — that is currently not being helped, and that is so vital for the economy. At present, we are building new homes for two broad groups of people. Of the roughly 30,000 homes that were built in London last year, a huge chunk were “affordable homes” of one kind or another, and then there was another sizeable chunk of top-end stuff – swish houses and apartments, often for foreign buyers.

We are not doing as the Victorians did, and providing new stock to be bought by the people in the middle – on household incomes from £30,000 to £64,000; and they are feeling utterly and understandably ignored. They cannot get the mortgages they would need, not at current prices, and not with lenders in their current mood. They have to live at a great distance from their place of work, and spend huge quantities on travel and hardly get to see their children in the evenings. They are obliged to rent at ever higher prices. In the past 10 years, the number of rented households in London has doubled, and rents went up 12 per cent last year alone.

The overwhelming majority of such people would like to buy, and to get on the same magic property escalator that has boosted the Milibands. It is time to help them. We in London have this month launched a “Housing Covenant”, an understanding between government and middle-income groups who work so hard, that we will put £100 million into building the good-quality homes that they need, and that they can buy.

Of course, Labour will object, and complain that every penny of subsidy should go to “affordable” homes for those, often on benefits, who cannot afford to buy at all. My answer is simple: this plan would help the very “squeezed middle” that Ed claims to espouse. We desperately need more housing not just for the poor, but for this vast and economically crucial group who are the motor of the London (and therefore of the UK) economy.

If we fail to cope with their needs, then the urban economics expert Prof Michael Ball has calculated that the resulting dislocation and inefficiency will cost us £35 billion in lost growth over 10 years. If we can make these investments in middle-income housing, we will boost the construction industry that provides so many jobs in itself, and we will enable the city to support the middle-income employees who drive the machine of the London economy that produces tax yields for everyone — and we will give them the same hope, the same trajectory, the same opportunity as the Milibands enjoy.

They say old school ties are strong in this country, but there is a limit. Yes, it is perfectly true that I was at the same school as the party leader, and yes, we went to the same university. I have absolutely nothing against him personally — he has a very nice wife, after all, and a good degree (admittedly in PPE). But the time has come to say it loud and clear: he is emerging as a total disappointment; and as leader of a major political party, he looks to me like a drip of the first order.

I refer of course to Edward Miliband. Yup, Ed and I were at the same superb school – Primrose Hill Primary School, Camden, a coincidence that he is curiously disinclined to mention – and it is only with great reluctance that I now break the ancient ties of fiefdom and fealty that knit one Old Primrosean to another. And in case anyone was for a second bamboozled by my cunningly phrased introduction, let me say now that the other old schoolmate/party leader, David Cameron, is not only doing a bang-up job on most fronts (apart from Latin – Georgic in my room by lock-up, please) but will be re-elected, for reasons I am about to explain, with an absolute majority.

Look, first, at the polls. According to yesterday’s YouGov, the Tories are only five points behind Labour — a measly five points, in the depths of what has been the longest and deepest recession many people can remember, when George Osborne is accused of slashing public services, and when many families have experienced a real deterioration in their standard of living. When Neil Kinnock was doing Ed’s job in the early Nineties, he managed to go about 24 points clear of John Major — and he still lost. What is wrong with Ed? The Tory strategists say it is all about his look, his manner, a certain teenage gawkiness compared to Dave’s look of Regency confidence; and that is certainly borne out by the polls. Dave wins big on who the voters both want to be PM – and, crucially, who they think will be PM.

But the Ed Miliband problem is more acute than that. Elections in this country, especially general elections, are not just about personalities. They are about programmes, about where you want to take the country, and it is here that Ed is getting it hopelessly wrong. Some Labour top brass accuse him of a do-nothing strategy, of trying to sneak into Downing Street with an exhibition of masterly inactivity. If only that were true. In so far as he has done anything with the Labour Party since taking over from Gordon Brown, Ed has moved it to the Left. He is back in the pocket of the union barons, at a time when many hard-working people are fed up with the self-aggrandising tendencies of union leaders, who often try to provoke strikes that are not in the interests of the workforce.

He has completely dropped New Labour’s sensible accommodation with the wealth creators of this country, and has not a good word to say about business large or small. Indeed he seems far more interested in finding new ways to tax, bully and penalise large private sector employers than in helping them to grow. He is the most nakedly redistributive Labour leader since Michael Foot, and when you dig into his notion of “responsible capitalism” it turns out to be all sorts of state control. He has done a total about-turn on education, with his education spokesman, Stephen Twigg, apparently junking the Adonis-led support for academies in sheer terror of the Lefty teaching unions.

In short, Ed has abandoned Blairism. He has torn up the playbook of the most successful Labour leader of modern times, a man who equalled Mrs Thatcher’s record and won three general elections. Blair understood that a Labour leader can only hope to win if he colonises the middle ground. You could vote for Blair and use private medicine. You could vote for Blair and send your children to fee-paying schools. You could vote for Blair and run a vast multinational corporation. As Ian Gilmour languidly remarked before the 1997 landslide, “ANYONE could vote for Blair.”

Tony Blair understood the voters’ doubts about Labour: they remembered the dominance of the unions; they remembered the exorbitant tax rates. They remembered the economic shambles. That is why Blair ingeniously presented himself as a man in constant conflict with the reactionary Left, a man who went so far as to dump his party and proclaim a new entity – New Labour. He didn’t cringe and fawn before the teaching unions; he took them on. He had the sense to see that Labour had bogged it up badly in the Seventies, and that people needed to see signs of change and repentance.

That is emphatically not what we get from Ed Miliband or Ed Balls. Much is made of the rift between the leader of the Opposition and his shadow chancellor, and no doubt there is plenty of scope in that relationship for the factional feuding and bickering at which all parties excel. But both Eds have this in common. They are one-time stooges of Gordon Brown, the man who spent his entire time in government engaged in a malevolent subterranean war against Labour’s number one vote-winning asset, Tony Blair. Both Eds were deeply complicit in that war; but worse, they were complicit in the spending and borrowing policies that helped to get this country, once again, into a serious economic mess.

The voters aren’t fools, and they want some thoughtful account of what Labour got wrong and why they wouldn’t get it wrong again; and with growth so painfully slow it is not good enough to talk — as Miliband does, endlessly – about bashing banks and raising taxes. Those are not growth-promoting measures. Over the next two and a half years the most likely political outcome is surely this: that the economy will steadily recover, and the signs of hope that we are now seeing will multiply. After enduring a long period of unpopularity, during which they did difficult but sensible things, the Conservatives will be rewarded for their patience. I have said it once and I say it again.